1. Field of the Invention
This invention relates to an electronic automatic transmission controller for automobiles and more particularly to such a controller whereby an automatic transmission is controlled by selectively combining the driving pattern of shift solenoids and that of a lockup solenoid which are controllably driven in accordance with shift solenoid pattern data and lockup solenoid pattern data.
2. Description of the Prior Art
It is well known that an automobile having an automatic transmission generally have an electronic controller whereby the position at which a speed is to be changed, i.e., to be shifted-down or shifted-up may be predetermined according to the shift pattern established from the interrelation between their speeds, engine loads and throttle opening percentage, and that further improveed automatic transmissions have a controller that operate a lockup solenoid when overdriving, to couple the engine output from the torque converter to provide the locking up. The lockup solenoid provides a mechanical direct-coupling thereof to the automatic transmission, thereby eliminating the power conveyance loss in the torque converter.
However, locking-up only when overdriving is not necessarily advisable upon consideration of the running characteristics of automatic transmissions. With a foward 4-speed automatic transmission, for example, locking-up in the 2nd- or 3rd- speed range according to the interrelation between their running speeds and throttle opening degree may be more advisable from the standpoint of fuel economy.